Automatic air-cushion.



G. W. MACKINNON. AUTOMATIC AIR CUSHION. APPLlCATlON FILED JUNE $8, 1915.

Patented Jan. 18,1916.

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G. W. MAcKINNON.

AUTOMATIC AIR CUSHION;

APPLICATION FILED mums. I915.

Patented Jan.18

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v GEOBGE VJ. MACKZNNON, OF BOSTON, MA$SACHUSETTS.

AUTOMATIC AIIt-GUSHIUN.

To all /101 it may concern Be it known that l, Gnome NON, a citizen of the United resident of Boston, in the county of Surf- 5 folk and State oil? Mass-aclnisctts have in- Yentcd a. new and improved Automatic Aji r- Cushion, oi which the following is a full, clcanand exact description.

This invention relates to carriages and 1D wagons and has particular rcibrcnco to automatic cushioning devices (or use between the frames and the axles of aulonmhilcs or other YQlllUlQS whcrcinfl the shock incident to the bouncingor recoil olf (ho springs is 1 5 avoided. i

Among the objects oi ihc inrculion is to provide acnshioning (lGYlCP- adapted to be easily and reliably connected to existing automobile structures at a minimum expense and involving an air cylinder and a piston therein supported upon a. cushion of air the'parts being so arranged that the cll'cctivcness of the cushion. is variable automatically in proportion to the load to be sus- W ith the foregoing; and other objects in View, the invention consists in the arrangement and combination of parts hereinafter described and claimed. and while the invention is not restricted to the exact details of constrnction disclosed herein, still for the purpose of illustrating a, practical embodimentthercof reference is had to the accompanying drawings, in which like reference characters designate the same parts in the several, views, and in which l igurc 1 is a plan view indicatingfragments 01? an automobile chassis having my iinprijn'c'd cusl'iioning devices applied there- 2 is a side elevation of the same, the wheels being omitted; Fin. 3 is a ver tical scctic al view of one of the air cushions; Fig. 4 Y: a side elevation of the same at right angles to the plane of the section of Fig. 3; and Fig.5 is atransvcrse section on the line 5 of Fig. 3. v

Referring now more particularly to tho dri'iwings, and by way of illustration of a preferred manner of connecting the cushion devices to a cmn'cntional type of auto mobile chassis, I show at 10 and 11 front -and rear axles of an automobile supported 1" Letters Patent.

Patented Jan. 1 8, 1916,

Application filed June 18, 1915. Seria11l'o.34,8l7.

npon front and rear wheels 12 and. 13. 14 indicates the longitudinal side bars of the chassis frame and 15 and 16 indicate the front and rear springs respectively.

While the function and operation of the springs '15 and 16 remain virtually nnafiectml by the application of this improvement to the vehicle, yet I provide means to regulate the speed of action of the springs within certain limits, especially to prevent the upward bonnci ellcct of the springs adding materially to the safety and life of the springs and comfort to the passenger". I apply therefore to the machine, preferably at each corner of the chassis adjacent the wheels, air rushii'ming' rlcric s preferably of the type shown in the detail views, each comprising a barrel or cylindcr 1'? having an anchor '18 in the form of an eycbolt tapped and hence adjustably secured in the (Dilllllti or closure 19 at one end of the cylinder, the adjustment of the cyebolt longitudinally of thc cylinder being fixed by means oi a loclc nut 20. The cyebolt is designed to he flexibly connected to a bracket 21 secured to or adjacent one of the axles, such connection permitting a hinge movenient forwardly or laterally in any direction but pliWLlli'llhL longitudinal displacement of the eycbolt and cylinder except as permitted by the ailjnstn'iont through the threaded shank.

l'Vithin the cylinder is'slidably fitted a piston 22 having an airtight packing ring 23 and having secured to the center thereot in any suitable manner a piston rod 24 extending througl'i a packing gland 25 in a cap 26 secured to the upper end of the cylindcr 17 in any suitable rigid air-tight mannor. The upper end of the piston rod has an eye 2% through which the piston is conin place by means of a lock nut 31 against its upper face.

At 32 is shown a tubular air port extending vertically through the piston and plate, the lower end of which is normally held closed by a flexible valve 33 secured at 34 on the side of the piston opposite the port 32 and opening downwardly relatively to the piston. The tube providing the air port extends somewhat above the upper surface of the plate 29 whereby any oil admitted into the upper'end of the cylinder will pass through the perforations 30 into the space 28 where it will be in position to keep the inner surface of the cylinder lubricated where acted upon by the packing ring 33.

I No free oil, however, will pass the piston and collect in the bottom of the cylinder. Oil may be introduced into the upper end of the cylinder in any suitable manner as, for instance, through an inlet 35 formed in the gland cap whereby the gland may be maintained lubricated as well as to supply oil into the interior of the cylinder.

The piston subject to the normal up and down vibration of the vehicle frame is adapted to float or reciprocate up or down in the cylinder, the normal carrying position, however, beingsubstantially midway between the ends thereof. Substantially midway between the ends of the cylinder is fitted an adjustable plug 36 providing in. connection with the cylinder wall an. adj ustable relief port 37. The area of the port 37 is varied by rotating the plug slightly around its axis. Near the upper end of the cylinder is provided another plug 38 having a similar variable port 39. The two ports 37 and 39 are designed to control the movement of air out of and into the interior of the cylinder exclusively. That portion of the cylinder below the port 37 being hermctically closed and the piston being fitted airtight in. the cylinder, all of the air trapped below the piston will act as a cushion resilien'tly sustaining the load. connected to the piston rod 24. As stated, the normal position of the piston is substantially as shown in 'Fig. 3, with a degree of compression of the air beneath it proportional to the load carried. It the machine runs into a chuckhole causing the load tomove-the piston downwardly, the cushion of air beneath it I will resist a too great downward thrust, and

it, together with the springs, wil l again lift the load, the upward movement, however, being retarded by the air cushion above the piston. admittrd through the inlet port 39.

'lhe degree to which the retarding effect op-' eiatcs will depend upon the area ot the inlet port. in other words, if the upward movementis to be made comparatively slow, the

inlet port will be restricted, and if a more rapid upward movement is desired it will be deliver airthrough the port 32 into the lower end of the cylinder. When, however, the amount of air entrapped beneath the piston overcomes the force of the load tending to hold th piston in its normal position sealing the outlet port 37, the excess air willpass automatically out through the port'37 until the piston sinks again to itsnormal position. It will be seen, therefore, that irrespective of the variations in loads carried by the inacliine, the piston will be maintained normally at about the same level.

I claim?! 1. In an automatic air cushion, the combination of a" 'igi l cylinder, means to anchor one end'of thecylinder in position fixed from longitudinal movement, said cylinder having adjustable inlet and outlet ports, a piston slidable within the cylinder with an airtight fit, a piston rod secured to the piston and extending thence through the opposite end of the cylinder, a packing gland surrounding the piston rod, a plate secured to the piston and providing an oil space between the plate and the piston, and an air port tube extending through the piston. andsplat'e, the upper end of the tube reaching al bv' the upper surface of the plate.

2. In an automatic air cushi n for automobiles, the combination of acylinder having variable inlet and outlet air ports, the outlet port being substantially at the longitudinal center of the cylinder, a piston slidably fitted in the cylinder with an airtight fit and operated normally just below the outlet port, said piston having an upwardly projecting hub, a perforated plate applied against the upper end of the hub providing an oil space between the plate and the main portion of the piston, a piston 'rod extending through the plate and into the hub and locking the plate thereto, an. air port tube extending through the piston and. plate parallel to the axis of the piston rod, a valvesecured to the lower portion of the piston and adapted to close the lower end of the 4 tube but opening downwardly on the upstroke of the piston, and means to supply oil into the upper P01131011 of the cylinder whence it passes through the plate into the aforesaid space.

3. The combination of an air cushion comprising a cylinder, a piston reciprocating therein in an airtight manner, means to admit air in regulatable quantities into the upper end of the cylinder, the piston being pro videcl with a passageway for the air to pass downwardly through the piston, a check valve to prevent the air t0 pass upwardly through the piston, and means adjacent the middle portion of the cylinder to regulate autrmmticnlly the quaniity of air below the piston according to the load sustained by the plston 1rrespect1ve of any verlatwns thereof.

GEORGE W. MACKINNON. *itnesses:

T. FRANK MALONEY, E. A. BYRNE. 

